Annual prostate cancer screening could benefit men with high inherited risk of cancer

New researched published in The Lancet Oncology suggests that men who have a high genetic risk for certain cancers through ‘Lynch syndrome’ could benefit from regular testing for prostate cancer.

Researchers believe that those aged 40 and above with Lynch syndrome should undergo PSA testing annually, as it could lead to earlier diagnosis and treatment of prostate cancer.

The test, which measures the level of prostate-specific antigen (PSA) in your blood, is thought to pick up cases of prostate cancer up to eight times as often in men with genetic hallmarks of Lynch syndrome – faults in genes like MSH2 and MSH6 – than in those without.

Lunch syndrome affects around 175,000 people in the UK, however, only five percent of people with the condition are aware they have it. This test could therefore help to save thousands of lives by enabling early detection and treatment.

Men with Lynch syndrome were up to eight times more likely to be diagnosed with prostate cancer than non-carriers

The study involved 828 male participants from families with Lynch syndrome at 34 centres in eight different countries. Of the participants, 600 have faults in the so-called mismatch repair genes MLH1, MSH2 or MSH6 which are associated with Lynch syndrome.

Out of 305 men with faults in the MSH2 gene, 13 (4.3 per cent) were diagnosed with prostate cancer, while only one non-carrier out of 210 (0.5 per cent) was diagnosed with prostate cancer.

For MSH6 carriers, four out of 135 men (3 per cent) were diagnosed with prostate cancer, while none of 177 non-carriers had a prostate cancer diagnosis (0 per cent).

Men with the MSH2 gene fault were therefore eight times more likely to be diagnosed with prostate cancer than non-carriers, and were diagnosed at a younger age – an average of 58 years compared with 66.

Some men with the MSH2 gene fault were also found to have more aggressive, potentially life-threatening tumours, with 85 per cent showing ‘clinically significant’ disease, compared with no non-carriers.

Meanwhile, MSH6 carriers were diagnosed at an average age of 62 years and 75 per cent had life-threatening, or ‘clinically significant’, tumours.

While PSA screening is not recommended for men in the general population due to concerns that it can lead to over-diagnosis and over-treatment of cases that would not have caused significant problems, the research suggests that over diagnosis in MSH2 and MSH6 carriers is unlikely.

PSA screening for men increases chance of survival

Future screening rounds will now help establish the benefits and any harms of annual screening in men carrying MLH1, MSH2 and MSH6 gene alterations, so that experts can conclude if screening should be introduced for these groups.

The researchers are also planning another five-year follow-up to compare treatment outcomes in these men. Subsequent screening rounds and detection of cancers will also be important in determining whether the PSA threshold of 3.0ng/ml used in this study is appropriate.

Professor Ros Eeles, Professor of Oncogenetics at The Institute of Cancer Research, London and Consultant in Clinical Oncology and Oncogenetics at The Royal Marsden NHS Foundation Trust, led the study. She said: “Targeted screening has the potential to pick out aggressive prostate cancers at an early stage in men at high inherited risk, increasing their chances of survival. And because cancers in these men are more likely to be aggressive and potentially life-threatening, they would need to have radical treatment.

“I anticipate that these results, and evidence from our ongoing follow-up work, will influence future national and international screening guidelines for this group of men, with the aim of picking out prostate cancer earlier and potentially saving lives.”